Batch files are really just text files, or small scripts which can be executed by command line processor - "cmd.exe", they where widely used in DOS environment for automation of common tasks.
EXE files are different from BAT files since they contain executable binary data rather than plain text commands. They are stored in the Portable Executable (PE) format. The EXE file format includes various headers and sections that tell Windows how to run a program. Some portions of an EXE file may contain program code while others may contain resource data.